doing or what the government represents. >> okay. well, brad garrett, thanks very much for that. we are continuing to get video from the scene there. that was in the moments after the explosion. i don't know, is richard clarke still with us? let me get back to pierre thomas instead. pierre, from what you're talking to we just heard brad garrett and he's carefully calibrating what he said right now, but are you getting any indication from law enforcement officials right now that they have any idea who might have been behind this? >> again, too early according to my sources. they will have a list of the usual suspects that they will put on the table. but really the key is to try to get that information from the scene to point them in a particular direction. but until that happens, when they have a particular avenue to pursue. what they will look at is they'll go back over all intelligence, some of it which may have been deemed not credible, did they miss anything? they'll comb back through the previous intelligence leading up to today